Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event.
Multi-touch screens or multi-touch panels are a further development of touch screens. These allow for the device to sense multiple touch events at a time. More specifically, a multi-touch panel can allow a device to sense the outlines of all fingers or other objects that are touching the panel at a given time. Thus, while a single touch panel may only sense a single location that is being touched, a multi-touch panel can provided an entire “touch graphic” which indicates the status (touched or not touched) of a plurality of touch pixels at the panel.
An exemplary multi-touch enabled display is disclosed by U.S. patent application Ser. No. 11/649,998 filed on Jan. 3, 2007, entitled “PROXIMITY AND MULTI-TOUCH SENSOR DETECTION AND DEMODULATION”, Pub. No. 2008/0158172 which is hereby incorporated by reference herein in its entirety for all purposes. Early multi-touch displays required manufacturing of a multi-touch sensing panel and a separate display panel. The two panels can later be laminated together to form a multi-touch display. Later generations of the technology provided for combining the display and multi-touch functionality in order to reduce power consumption, make the multi-touch display thinner, reduce costs of manufacturing, improve brightness, etc. Examples of such integrated multi-touch displays are disclosed by U.S. application Ser. No. 11/818,422 filed on Jun. 13, 2007 and entitled “INTEGRATED IN-PLANE SWITCHING”, and U.S. application Ser. No. 12/240,964, filed on Jul. 3, 2008 and entitled “DISPLAY WITH DUAL-FUNCTION CAPACITIVE ELEMENTS,” both of which are incorporate by reference herein in their entireties for all purposes.
However, some of the schemes for integration can require placing some additional non-transparent elements in the thin film transistor (TFT) layer of the display. Such additional non-transparent elements can reduce the aperture of the display (the aperture being the portion of the display that actually transmits light). Reduction of the aperture can cause reduction of the brightness of the display as well as a reduction in the viewable angle of the display.